v0.7.67

• [web] New label type: area text. A text block that wraps at a user-defined width.
• [web] Callout lines can be added to labels in the label styles panel. Curved, straight and elbow callouts are supported, with or without arrowheads.
• New label style option: halos
• [web] All layers are now visible by default, so a layer used as a guide stays on the map when a new layer is created or imported. The -a/--display-all option of mapshaper-gui and the display-all URL variable are no longer needed, and are ignored.